This Present Disclosure relates to earphones that possess an outer ear canal insertion component for which at least a portion is to be inserted into the outer ear canal.
Formerly, as an earphone used by being mounted on the outer ear, there have been known those of the type called earphone headphones, which do not provide a protrusion to be inserted into the outer ear canal, and so-called insertion type earphones, which insert into the outer ear canal an ear pad constituted of such as soft rubber having elasticity (see Japanese Patent Application No. 2008-109206, for example).
FIG. 12 is an exploded view drawing that shows the structure of the former technology earphone. In the drawing, 811 is the earphone housing, and within housing 811 there is installed driver unit 841 that provides a vibration plate. Additionally, at the leading end of housing 811 (lower right end in the drawing), there is integrally connected the base end of acoustic conduit 817 which extends in toward the lower right. Within acoustic conduit 817 there is formed a sound conducting hole with passage through the space within housing 811, and inner cylinder member 817a is inserted. At the periphery of acoustic conduit 817 there is mated and attached ear pad 850 constituted of such as a soft rubber. As such, when the earphone is mounted, the leading end of ear pad 850 is inserted into the outer ear canal. Sound generated by vibration of the vibration plate of driver unit 841 passes through the hole within acoustic conduit 817 and ear pad 850 and enters the interior of outer ear canal, after which it arrives at the eardrum.
Furthermore, at the aft end of housing 811 (left upper end in the drawing), there is installed cover casing 814, and between cover casing 814 and housing 811 there is disposed cable support 815 having a duct shape that extends downward. Within cable support 815 there is housed electric cable 891. Lead wire 892 is exposed from one end of this electric cable 891, and the leading end of the lead is connected with conductive capacity to driver unit 841. The other end of electric cable 891, which extends from the lower end of cable support 815, is connected to an audio device not shown in the drawing, being such as a music player, television, radio, or video deck.
If electric cable 891 is pulled from the outer side, there is potential for the connection with driver unit 841 to become broken, and electric cable 891 may become separated from housing 811 and cable support 815. For that reason, knot 891a is formed at the end section of electric cable 891, and it is housed in a space within cover casing 814. Knot 891a is of a size sufficiently larger than the inner diameter of cable support 815 that it will catch on the upper edge of cable support 815 when electric cable 891 is pulled from the outer side, and therefore it functions as a stopper. This enables preventing the separation of electric cable 891.
Moreover, cylinder-shaped first elastic member 871 is disposed and box-shaped second elastic member 872 is disposed, in a formation to enclose the periphery of driver unit 841. First elastic member 871 and box-shaped second elastic member 872 are constituted of an elastic material such as silicon rubber, synthetic rubber, or an elastomer, they are disposed so as to be embedded between the inner surface of housing 811 and the outer surface of driver unit 841, and they position driver unit 841 while elastically supporting driver unit 841 fore and aft and around the periphery.
However, with the earphone of the prior art described above, first elastic member 871 and box-shaped second elastic member 872 set the position of driver unit 841 within housing 811, and therefore a deformation of first elastic member 871 and box-shaped second elastic member 872 reduces the precision of the placement of driver unit 841. In particular, if a manual operation is used to install driver unit 841, first elastic member 871 and box-shaped second elastic member 872 to within housing 811, it may generate large variations in the amount of deformation of first elastic member 871 and box-shaped second elastic member 872, thereby greatly reducing the precision of the placement of driver unit 841.
Furthermore, because first elastic member 871 and box-shaped second elastic member 872 are embedded between the inner surface of housing 811 and the outer surface of driver unit 841, and because they adhere to the outer surface of driver unit 841, there is inability to maintain a space at the periphery of driver unit 841. Even though the space within housing 811 is a acoustic space that applies significant impact on the acoustic performance of the earphone, that space is occupied by first elastic member 871 and box-shaped second elastic member 872, and thereby the acoustic performance of the earphone is impaired.